Berislav said:
Do you know who's the intended target audience? The general public, non-specialists?
I gather the book has [EDIT: Peter says technical parts, not equations though], indicating that at least part of the intended audience would be
OTHER physicists, not string theorists
and also students in the sciences, particularly grad students
like those Woit teaches at Columbia
(he is in the Mathematics department and sometimes gets the job of teaching the graduate-level courses in Quantum Field Theory and Group Representation Theory---graduate level math courses for physics students)
but it is complicated by the fact that the book was originally written for publication by Cambridge University Press
(with a less provocative subtitle, more academic-sounding)
then when he switched to a commercial publisher, they wanted him to get rid of [EDIT: the technical portions] (i.e. go for sales to the general audience)
and he fought that and with Roger Penrose help he managed to keep the harder stuff in, but even so the commercial publisher insisted on changing the subtitle and putting in the provocative attention-getting "failure of string theory".
So the answer is not clear-cut this or that. he wants other physicists, he wants an audience of scientists and university students, and he has not DUMBED DOWN the book, but he also wants general audience----and his publisher wants to promote the book so it will sell to general audience.
Berislav, this is the best I can do by way of answer to your question----I don't have enough information and must be partly relying on guesswork.
A good discussion of the background of the book, and the various changes of publisher and related decision, is at Woits blog
see blog discussion:
http://www.math.columbia.edu/~woit/wordpress/?p=245#comments
Look at Peter's original post, at the top, there
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I edited this in accordance with better information from PW in a post later on in this thread, that cleared up a misconception I had.